Study of Environmental Stress Signaling in Bacillus subtilis via components of RsbR paralogues

Bacillus subtilis has found to respond the signals of environmental and metabolic stress by inducing over 40 general stress genes which are under the control of the sigma B transcription factor. Sigma B is an alternative sigma-factor in Bacillus subtilis. It mediates the response of the cell to a variety of physical insults. General stress response of Bacillus subtilis is regulated directly by a partner-switching mechanism via key protein interactions and transcription factor sigma B expression plays important role on it. Physical stress is communicated to sigmaB via a large-molecular-mass (>106-Da) structure (i.e. called the stressosome) formed by one or more members of a family of homologous proteins (RsbR, YkoB, YojH, YqhA). Signals of energy or environmental stress are conveyed to sigma B by independent pathways, each terminating with a differentially regulated serine phosphatase (i.e. for serine phosphorylation), whose activity is required to control the partner-switching regulators. In B. subtilis genome, six paralogous proteins such as YetI, YezB, YkoB, YojH, YqhA, and YtvA are found which has significant similarity to RsbR. Key word: Bacillus subtilis, RsbR, environmental stress, sigma B genes, pathways __________________________________________________*****_________________________________________________